This disclosure relates in general to surveying systems and, but not by way of limitation, to determining spatial relationships between different positions. A theodolite is a surveying instrument used in surveying building construction and is used to measures angles for two degrees of freedom. A total station (sometimes referred to as a total station theodolite (TST)) is an electronic theodolite integrated with an electronic distance meter (EDM). The EDM measures a distance from a particular point to the EDM. Surveying allows land and structures to be accurately measured.
Global navigation satellite systems (GNSS), such as the Global Positioning System (GPS), can provide accurate positioning. For example, two GPS receivers are placed on two ends of a blade of a bulldozer to provide accurate three-dimension (3D) grade control for bulk earthwork, grading, and/or finish grading using the bulldozer. An example of a commercial system for 3D grade control is Trimble's GCS900 with GradeMax Plus.